1. Field of the Invention
The present invention relates to a screen for use as a window shade or a sun blind in a window frame, for example, to provide soft natural lighting, and more particularly to a pleat screen composed of a screen sheet having a multiplicity of horizontal pleats arranged side by side in the vertical direction.
2. Description of the Prior Art
Pleat screens usually comprise a screen sheet as of paper or cloth pleated into zig-zag folds, and are vertically foldable and unfoldable by a lift cord to open and close the window. When the pleat screen hanging from a window frame is unfolded, however, the pleats are spaced by their own weight more widely at an upper portion of the screen than they are spaced at a lower portion thereof, resulting in an unsightly appearance. This tendency becomes stronger as the screen is hung for a longer period of time. In such a situation, upper pleats go elongated or stretched completely so that the pleat screen can easily curve back and forth as a whole under the pressure of winds applied.